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Patient Controlled Analgesia

What is Patient Controlled Analgesia (PCA)?

Patient Controlled Analgesia (PCA) allows you to self-deliver small doses of pain medications through a machine.  Medications used in the PCA pump are opioid pain medications such as morphine or hydromorphone (dilaudid).


The PCA pump attaches to the IV (intravenous) line in your arm. When you have pain, you press the button and the pump delivers the medication into your IV. You can do this whenever you have pain – you do not need to tell the nurse first.


Your nurse will regularly check that you are getting appropriate pain control from the pump. For some patients, the Perioperative Pain Service Anesthesiologist and/ or Nurse Clinician (VGH) or the Clinical Nurse Specialist for Pain Management (St Paul’s) will evaluate you daily while you have the PCA. If you have any questions about your  PCA, ask your nurse or the visiting Anesthesiologist.


How do I use the PCA button?

You can press the PCA button whenever you have pain.  Once you push the button, the PCA pump delivers a dose of pain medication. The pump has built-in timers which prevent you from getting another dose for approximately 5–10 minutes. This means that if you push the button within this time, the PCA pump will not give another dose.


This allows enough time for the pain control medication to work before getting another dose. Remember, the aim is to make you comfortable – it is not possible to be completely pain free.

Remember to press the button 5–15 minutes before you move in bed or want to get out of bed. If after 15 minutes you are still too sore to move or cough, press the button again. This will help to make you comfortable enough to participate in physiotherapy.


Who is allowed to press the PCA button?

The safety of a PCA is that you are the ONLY person allowed to press the button. Hospital staff, relatives or friends are NOT allowed to press the button for you.

Will the pain control drug work immediately?

No. These medications need to get to the brain and spinal cord so it may take 5 minutes or longer to get the full effect.

Again, if you are about to do something that you know will hurt, like coughing or moving, press the PCA button about 5–15 minutes before doing it.


What will happen if the pain medication does not work?

If you are pressing the PCA button often and your pain is not controlled, tell your nurse. The nurse will assess, troubleshoot, and alter the dose as needed. If necessary, your nurse will contact your doctor or the pain service Anesthesiologist.

Can I overdose?

PCA is one of the safest ways of giving opioid pain medications. The dose that you get with each press of the button is very small. If you press the button too soon after your last dose, medication will not be delivered. This prevents you having too much, too soon. If you are getting too much medication, you will feel sleepy thus you will not press the button again. Your nurse will also notice this and may reduce the amount of opioid medication delivered with each push of the button and, if necessary, treat the sleepiness. The nurse will watch you closely.


How long will I use PCA?

When your doctors allow you to drink, it means that your IV may soon be removed. Your pain management medications will be transitioned from the PCA to pills.


What are the side effects of opioids used in the PCA?

As with most medications, there are possible side effects to medications used in the PCA pump. If any of these occur, it is important you tell your nurse or doctor.

  • Sleepiness Opioid pain medications may cause you to feel very sleepy. If this becomes a problem, adjustments can be made to your PCA dose. If extreme sleepiness occurs, medication is available to reverse the sleepiness.

  • Nausea and vomiting - this can occur because of surgery, the medications used in surgery, or from the PCA medication. Whatever the cause, medication is available to help control nausea.

  • Itchiness Sometimes the medication can cause your skin to itch. Putting cool packs and lotion on the itchy areas may help.  Medication is also used to treat the itchiness.

  • Bladder retentionSometimes the opioid used to reduce the pain may also block the message for you to pass urine. If you do not have a urinary catheter in place, it is important to tell your nurse if you have not passed urine within 4 hours.

  • Constipation All opioid medications can cause constipation. It is important to keep hydrated and eat foods that help to keep your bowel healthy. If you are concerned about constipation, ask your nurse for an appropriate laxative.

Can I get addicted to morphine-like medicines?

When you take opioids such as hydromorphone, morphine and oxycodone for acute pain, the risk of dependency and addiction is small. However, long term use of opioids may lead to dependency and addiction. The role of these medications is to make you comfortable enough to move, cough, and perform your physiotherapy. It is important to balance this risk with meeting your recovery goals. To reduce your risk of dependence and addiction, you should transition off the PCA to oral pain  medications as soon as you can, and then taper off oral opioid medications when the pain improves.




Vancouver Acute & St Pauls Hospitals acknowledge the contribution of Calgary Health Region Canada and the Royal Adelaide Hospital Australia in the development of this patient pamphlet.

Reviewed by Clinical Nurse Specialist - Perioperative Pain - VGH 2011

Reviewed by Providence Health Pain Management Initiative Committee 2011

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